Cabinet

ABSTRACT

Cabinet has a top frame and base frame around which the housing is wrapped on three sides so that the top frame and base frame define the size of the cabinet and provide dimensional rigidity to the housing. The housing is bent from a single panel of honeycomb material. Front closure frames have tongues extending into grooves in the front edges of the housing for adjustment during assembly to finalize front-to-rear dimensions of the cabinet and provide a planar cabinet front.

ilited States Pate Jamison et al. I

[451 Dec. 10, 1974 1 CABINET [75] Inventors: John W. Jamison, CostaMesa; Dan

R. Veronda, Fullerton; Roy E. Denner, Placentia, all of Calif.

[73] Assignee: Hughes Aircraft Corporation,

Culver City, Calif. [22] Filed: Feb. 9, 1972 21 Appl. No.: 224,839

[52] US. Cl. 312/259, 312/257 R [51] Int. Cl. A47b 43/00, A47b 47/00[58] Field of Search 312/214, 357, 138, 262 T;

[56] References Cited UNITED STATES PATENTS 1,496,525 6/1924 CoCo 49/5052,149,882 3/1939 Clements 312/259 UX 2,226,670 12/1940 Pratt et a1.312/214 2,274,765 3/1942 Zalkind 312/258 UX 2,360,451 10/1944 Stone312/257 R 2,477,942 8/1949 Renton 49/505 X 2,678,705 5/1954 Haines eta1. 312/257 UX 3,118,559 1/1964 Stricker et a1. 1 i 220/14 X 3,297,1891/1967 Carrasse .[312/214 X 3,472,571 10/1969 Himelreich 312/2593,485,545 12/1969 Newman et a1 312/258 3,675,809 7/1972 McGrew 220/9 BR22,425 1/1944 Rosenthal 312/259 Primary Examiner-Paul R. GilliamAttorney, Agent, or FirmA. A. Dicke, Jr.; W. H. MacAllister, Jr.

[ 57 1 ABSTRACT Cabinet has a top frame and base frame around which thehousing is wrapped on three sides so that the top frame and base framedefine the size of the cabinet and provide dimensional rigidity to thehousing. The housing is bent from a single panel of honeycomb material.Front closure frames have tongues extending into grooves in the frontedges of the housing for adjustment during assembly to finalizefront-to-rear dimensions of the cabinet and provide a planar cabinetfront.

4 Claims, 8 Drawing Figures PATENTE' LEE 1 01974 sum 1 nr 2 CABINETBACKGROUND This invention is directed to a cabinet, and particularly acabinet which can be subjected to dynamic laods associated with shockand vibration environments, and for enclosure of equipment, such aselectrical equipment.

The prior art includes many styles of cabinets for enclosing varioustypes of goods in different environments. Cabinets are employed tosupport equipment and to protect equipment from the externalenvironment. In the most difficult cases, the external environmentincludes dynamic loading with the presence of shock and vibrationapplied to the cabinet. Such environments are found in many militaryapplications, in the air, on the land, and on the water. In these cases,the cabinet must be sufficiently strong to withstand the dynamicloading.

Two basic approaches have been used in previous cabinets to which suchdynamic loading is to be applied: the corner-post" design and astiffened sidewall construction. The corner-post design is characterizedby rigid, heavy posts at each of its corners, with reinforced shearpanels on the sides and back. The loads developed within the cabinet dueto dynamic loading of the cabinet are routed to the corner posts bymeans of brackets, and then are transferred to the base and top supportof the cabinet through the corner posts.

The piece-part assembly approach inherent in the corner-post designnecessitates many mechanical fasteners and welding. With increasedloading intensities and/or payload increases, it becomes necessary toreinforce the walls of the cabinet with gross additions of stiffeners,including hat sections, doublers, and stringers. While these stiffenersprovide additional crosssectional moment of inertia, they also increasemanufacturing costs, because a considerable amount of assembly time isrequired for the installation of such stiffeners. The corner-post designof cabinets for dynamic loading is thus shock-load limited, i.e., athigh load intensities, the amount of routing bracketry and stiffenersneeded to transfer the loads from within the cabinet to the base and topis of such magnitude that the cabinet is excessive in cost and weight.

The present alternative construction to cabinets of the corner-postdesign for high load environments comprises cabinets of stiffenedsidewall construction. The

stiffened sidewall construction relies on large crosssectional moment ofinertia of the cabinet sidewalls. These sidewalls distribute loadsdeveloped within the cabinet and thus are capable of high dynamic loads.The sidewalls may be built up using bracket-like piece parts, or theymay be extrusions. The extrusion sidewalls are generally 1% to 2 inchesthick. In such construction, the cabinet backwall is merely a thin shearpanel which is welded to the stiffened side panels.

In theory, the stiffened sidewall construction reduces the number ofpiece parts while, at the same time, provides added stiffness to supportlarger payloads in high loading environments. However, like thecorner-post design, the cabinets which employ built-up sidewalls arealso shock-load limited. Cabinets having extruded sidewalls do not havethis limitation. However, extrusions are major elements in suchconstruction and necessitate expensive dies. Of course, a panel producedSUMMARY In order to aid in the understanding of this invention, it canbe stated in essentially summary form that it is directed to a cabinethaving a unitary housing extending around two sides and the back andsecured to a frame which holds the housing to size. In one aspect of theinvention, the housing is of laminated panel construction and, inanother aspect, the housing has grooves in the front edge thereof intowhich a front closure frame extends.

Accordingly, it is an object of this invention to provide a cabinetwhich is suitable for the housing of equipment in an environment subjectto dynamic shock and vibration loading. It is another object to providea cabinet which has a one-piece housing extending around the sides andback of the cabinet. It is another object to provide a singlewrap-around housing of metallic skin material which shields theequipment enclosed within the cabinet to reduce the level of radiofrequency interference and electromagnetic interference between thecabinet contents and the exterior environment.

It is a further object to provide a cabinet which has a frame basearound which the housing is wrapped, which frame base establishes theexterior dimensions of the cabinet housing. It is a further object toprovide a cabinet having a housing formed of honeycomb panel forstrength and lightness of weight, consistent with a dynamic environment.It is another object to provide front closure frame sections which areadjustable with respect to the cabinet housing so that the front of thecabinet can be adjusted during manufacture. Other objects and advantagesof this invention will become apparent from a study of the followingportion of the specificatiomthe claims, and the attached drawings.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is an isometric view of acabinet constructed in accordance with this invention.

FIG. 2 is an exploded view of the cabinet showing the major partsthereof.

FIG. 3 is an enlarged vertical section, with parts broken away, takenalong the line 3-3 of FIG. 1, showing the details of the upper front andrear corners.

FIG. 4 is an enlarged horizontal section through the cabinet near thebase, taken generally along the line 4-4 of FIG. 1.

FIG. 5 is an enlarged vertical section, with parts broken away, takengenerally along the line 5-5 of FIG. 4.

FIG. 6 is an enlarged horizontal section, with parts brokenaway, throughone of the front corners of the cabinet of FIG. 1, taken generally alongthe line 6-6 of FIG. '1 showing the preferred embodiment of the frontclosure frame. 1

FIG. 7 is similar to FIG. 6 showing another embodiment of the frontclosure frame.

FIG. 8 is also similar to FIG. 6 showing a third embodiment of the frontclosure frame.

DESCRIPTION The cabinet 10 illustrated in FIGS. 1 and 2 is an example ofthe cabinet construction, in accordance with this invention. Theparticular cabinet illustrated in these figures is exemplary of thevarious sizes and styles in which a cabinet can be built, in accordancewith this invention. Various other configurations employing the conceptsof this invention can be constructed.

The cabinet 10 comprises a cabinet housing 12 which forms the side andback of the cabinet. The cabinet sides are indicated at 14 and 16, withthe back shown at 18. Housing 12 is illustrated in its preferredembodiment as being a laminated honeycomb panel. In the preferredembodiment, it has a metallic inner and outer skin and a metallichoneycomb therebetween. Preferably, all are aluminum and are securedtogether as by adhesive. Other forms of honeycomb can be used but, inany case, at least the outer skin should be metallic. In some cases, acore material in the housing between the skins of rigid syntheticpolymer composition foam would be useful. Furthermore, several layers ofcore material, such as a layer of metallic honeycomb and a layer ofpolymer composition rigid foam, with a divider skin, can be used. Asanother embodiment, the housing can be a single layer of material, suchas bent sheet metal, but this type of construction does not have thedynamic load-resisting properties that a metallic honeycomb has. Thus,the preferred embodiment is a metallic honeycomb with aluminum inner andouter skins, as well as aluminum honeycomb.

The bending of honeycomb material into suitable configurations for useas a cabinet housing is taught in more detail in US. Pat. No. 3,753,559.The entire disclosure of that patent is incorporated herein by thisreference. See also its division, Ser. No. 351,699, filed Apr. '13,1973. In summary, a flat, laminated, metallic honeycomb panel can bebent from planar condition into a shaped condition having cornerstherein by bending the inner skin outward to crush the honeycomb betweenthe skins in the region of the bend. The bends of the inner and outerskins are such that the surface distance around the bent corner is thesame on the inside skin as on the outside skin so that the laminatedhoneycomb panel away from the bend is not appreciably distorted, butremains planar, with its normal strength characteristics. Such bends areillustrated at the rear corners of the cabinet 10 in FIGS. 2 and 4.

Prior to bending, the housing 12 is built up into flat panel. It is laidup with aluminum closeout blocks along the upper and lower edges, exceptin the bend areas. These closeout blocks structurally reinforce theedges of the cabinet and are utilized to obtain a solid attachment.Additional cutouts for connectors, air venting, etc., are also closedout with aluminum blocks to provide adequate structural termination atthe edges of the skin. Aluminum honeycomb core material fills theremaining portion of the sandwich core, with aluminum skins completingthe panel.

While in flat condition, the panel can be inspected, inserts made andpotted in place, and the like. Furthermore, cutouts can be machined,base bolt holes can be drilled and threaded so that details of thehousing 12 can be manufactured with a minimum of difficulty with thehousing panel in the flat condition. When built up in this way, thealuminum skins carry the load in the plane of the panel, while the corecarries shear stresses and resists compression loads normal to the planeof the panel. When in the formed condition, after the corner bends aremade, shock loads imparted to the cabinet will be absorbed in shear bythe honeycomb core and transferred uniformly to the panel skins.

Once in the formed condition, the housing 12 is maintained in shape anddimensionally stabilized by means of top frame 20 and base frame 22. Asseen in FIGS. 2 and 3, top frame 20 is of rectangular configuration ofsuch size as to equal the interior dimensions of the finished cabinet.It is formed of structural angle. Shear bolts 24 engage through the topframe into the closeout bar 26 positioned between the skins of thehoneycomb at the upper edge of back 18. A plurality of these shear bolts24 are positioned around the sides and back of top frame 20 and engageinto the corresponding parts of the upper end of housing 12. These boltspull the housing into shape and keep it that way.

Similarly, base frame 22 is secured within housing 12 at the lowerportion thereof to serve as the bottom of the cabinet. In normal dutyoperations, shearbolts such as shear bolts 24 can be engaged outwardthrough the base frame into a closeout bar on the bottom of housing 12.However, in higher dynamic duty circumstances, as in the preferredembodiment, tension bolts 28 have their heads positioned interiorly ofthe flanges of base frame 12 and extend outwardly to be threaded intocloseout bars 30 and 32 positioned on the bottom of sides 14 and 16 inthe bottom of back 18. These tension bolts 28 draw the bottom of housing12 into dimension and shape and hold it there. However, in order toendure even heavier dynamic loading, additional bolts are engagedthrough the bottom of the housing 12 and base frame 22. Shear bolts 34have heads in counter bores recessed into the exterior of housing 12,into the closeout bar in the bottom thereof, and these shear boltsextend through base frame 22 to have securing clamp nuts thereon, asseen in FIG. 4. This provides a highly rigid structure and securementbetween the housing 12 and base frame 22. The base frame 22 has boltdownholes'36 in the corners to bolt down the entire cabinet 10 onto anappropriate base. In dynamic loading environments, the top frame is alsopreferably secured to the environment base. These two frames, the topframe 20 and base frame 22, to which the housing 12 is secured, providea unitary rigid structure. In order to protect the top from theelements, cabinet cover 38 is secured down over the top of top frame 20in the upper ridges of the housing 12.

As illustrated in FIG. 2, the upright front edges of the left and rightsides 14 and 16 of housing 12 have closeout bars 40 and 42 positionedbetween the skins and abutting the honeycomb. FIG. 6 illustrates thecloseout bar 42 in more detail. Closeout bar 42 has a groove 44 therein,and a similar groove 46 is formed in the front edge of closeout bar 40.These grooves 44 and 46 have parallel sidewalls to receive the tonguesof front closure frame.

In the preferred embodiment shown in FIGS. 2 and 6, front closure frames48 and 50 are L-shaped, including tongue 52 which extends into thegroove 44. The two front closure frames 48 and 50 are adjusted so thatthe front-to-back dimension of the cabinet is correct. Thereupon, thefront closure frames are secured into place, as by rivets 54 and,preferably, additional adhesive securement. Door 56 is, thereupon,pivotally mounted upon frame 50 by appropriate hinges so the door servesas an access closure to the interior of cabinet 10.

In the embodiment of Fig. 7, front closure frame 58 comprises a tongue60 to which is secured a front closure bar 62. These parts are boltedtogether with clearance around the bolt shank so that lateral adjustmentof front closure bar 62 is possible. Such provides the desirable lateralopening size adjustment of the door opening.

in FIG. 8, the front closure frame 64 is as wide as the thickness of thehousing. Such construction is desirable where there may be a pluralityof doors, or where a minimum construction thickness is required. Withrespect to the constructions of FIGS. 7 and 8, after the frames areadjusted, the tongues are secured in place by rivets and, preferably,also by adhesive means, similarly as described with respect toconstruction of FIG. 6.

From this construction, it can be seen that the housing 12, being of asingle sheet of material bent into configuration to define the sides andback of the cabinet, serves as the primary load-bearing element of thecabinet. The front closure frames carry a proportion of load, and alsoserve to form the cabinet front and define the door opening. ln extremevibration environments, the front closure frames structurally reinforcethe cabinet sidewalls, especially when the cabinet is excited byside-to-side vibrational inputs. The front closure frames are boltedthrough to the base frame 22 to provide a unitized construction, therebyincreasing its stiffness characteristics. The load-bearingcharacteristics of the housing 12 result from its sandwich laminateconstruction, it being formed out of a single piece of material havingstrength in bending and shear. As stated above, the material of thehousing is preferably aluminum honeycomb.

Cabinet 10, thus, is constructed in such a manner as to be economic ofconstruction and yet be suitable for dynamic loads, such as shock andvibration. The construction is such that radio frequency interferenceand electromagnetic interference between the cabinet contents and theexterior environment is minimized. Simple modifications of the base andhousing permit different shapes and dimensions which are able toaccommodate wide variations in payload, load distribution, cabinetgeometry, top support and environmental require-.

ments. Furthermore, the design lends itself to the latest manufacturingtechniques. For example, tape control drilling machines can be employedfor speed and accuracy to locate threaded inserts in the flat housingstructure before bending. In this way, no expensive dies, moulds, ortooling are required, and a high-strength cabinet is provided.

This invention having been described in its preferred embodiment, it isclear that it is susceptible to numerous modifications and embodimentswithin the ability of those skilled in the art and without the exerciseof the inventive faculty. Accordingly, the scope of this invention isdefined by the scope of the following claims.

core therebetween attached to and rigidizing said metal skins with thehoneycomb core cells being normal to said skins, said panel being bentat the cabinet corners so that said panel defines the sides and back ofsaid housing, said honeycomb core being crushed at said corners and saidpanel skins extending continuously around said corners, said panel beingsecured to said top frame and said base frame so that said top frame andsaid base frame retain said panel in a lateral position, said laminatedhoneycomb panel carrying the principal physical loads on the cabinet;

a closeout bar positioned between the panel skins at each of said edges,said closeout bars each having means for interengaging thereon;

front closure frames, said front closure frames each having means forinterengaging thereon, said means for interengaging on said frontclosure frames being interengaged with said means for interengaging onsaid closeout bars.

2. The cabinet of claim 1 wherein said front closure frame has alaterally extending front closure bar thereon for defining a dooropening in the front of said cabinet.

3. The cabinet of claim 1 wherein said means for interengaging comprisesa groove and a tongue within said groove, said tongue and said grooveeach having substantially parallel sides so that said front closureframe can be adjustably positioned with respect to said housing whilesaid tongue is at least partially positioned within said groove. 1

4. The cabinet of claim 3 further including a door hingedly mounted uponone of said front closure frames and extending substantially to theother of said net.

1. A cabinet for the enclosure of equipment, said cabinet comprising: a base frame defining the lateral dimensions of said cabinet; a top frame further defining the lateral dimensions of said cabinet; a unitary housing defining left and right sides and back of said cabinet, with a forward-facing edge on each of said left side and said right side, said housing being formed of a single panel of laminated material having a metal inner skin, a metal outer skin, and a honeycomb core therebetween attached to and rigidizing said metal skins with the honeycomb core cells being normal to said skins, said panel being bent at the cabinet corners so that said panel defines the sides and back of said housing, said honeycomb core being crushed at said corners and said panel skins extending continuously around said corners, said panel being secured to said top frame and said base frame so that said top frame and said base frame retain said panel in a lateral position, said laminated honeycomb panel carrying the principal physical loads on the cabinet; a closeout bar positioned between the panel skins at each of said edges, said closeout bars each having means for interengaging thereon; front closure frames, said front closure frames each having means for interengaging thereon, said means for interengaging on said front closure frames being interengaged with said means for interengaging on said closeout bars.
 2. The cabinet of claim 1 wherein said front closure frame has a laterally extending front closure bar thereon for defining a door opening in the front of said cabinet.
 3. The cabinet of claim 1 wherein said means foR interengaging comprises a groove and a tongue within said groove, said tongue and said groove each having substantially parallel sides so that said front closure frame can be adjustably positioned with respect to said housing while said tongue is at least partially positioned within said groove.
 4. The cabinet of claim 3 further including a door hingedly mounted upon one of said front closure frames and extending substantially to the other of said front closure frames for closing the front of said cabinet. 